Pallet

Abstract

A pallet is provided having spaced apertured blocks of rigid foam polymeric material bonded or otherwise secured between layers of corrugated paperboard. The pallet may be rendered substantially waterproof. In one embodiment, C-shaped support members may be connected to at least some of the edges of the pallet. Openings may be provided in the C-shaped support members to permit the tines of a fork lift truck to engage the pallet to effect movement thereof. When the C-shaped support members are secured to each of the edges of the pallet, the pallet will be rendered substantially waterproof. In another embodiment, the bottom layer of corrugated paperboard may be eliminated and the top layer utilized to envelop some of the blocks. An intermediate strip of corrugated paperboard may be used to provide a base for the remaining blocks.

Parent Case Text

This application is a continuation-in-part of my prior application Ser. No. 622,808 filed Mar. 13, 1967, for "Pallet" now U.S. Pat. No. 3,380,403.

Description

My prior application was directed primarily to an expendable pallet which was to be used once and thereafter discarded. The pallet set forth in my previous application has filled a long existing need in industry and is excellent for its intended use. However, due to the superior features of my expendable pallet, such as low cost and weight factors, there has been an increasing demand that the pallet has been made sturdier, more durable and substantially waterproof. Accordingly, the present invention is directed to an inexpensive, lightweight, substantially waterproof, sturdy and durable pallet which may be reused many times without substantial deterioration of the pallet.

In plants where pallets are utilized to convey goods along a production line, and the pallets are made of wood, the pallets present a substantial problem. Because of the weight of wooden pallets, it has generally been necessary to provide a man at the end of a production line to remove the pallet from the conveyor line. In many instances, one man can service two production lines to remove and stack the cumbersome and heavy wooden pallets. Furthermore, intraplant use of the pallets has substantially increased to convey goods throughout various locations in a single plant. Accordingly, it is desirable to provide a pallet having the features of my expendable pallet but which is adapted to be reused many times without noticable deterioration of the pallet.

It is an object of the present invention to provide a pallet which is light in weight and inexpensive to manufacture and yet sturdy and durable in use. This is accomplished by providing blocks of rigid foam ply polymeric material which are bonded or otherwise secured between layers of corrugated paperboard. The blocks of polymeric material are provided with a plurality of holes therethrough. The provision of such holes has various advantages. Thus, the provision of such holes enables the blocks to be molded more consistently and provides for more uniform heat distribution so that the blocks may be molded at a faster cycle as compared with solid blocks. In addition, the holes will trap air when sandwiched between layers of paperboard and thereby offer resistance to crushing under the load supported thereon.

In one embodiment, after the pallet has been assembled, C-shaped support members may be secured to the side edges thereof. The C-shaped support members prevent damage to the blocks of polymeric material should the pallet be dropped or otherwise mishandled. The C-shaped support members may render the pallet substantially waterproof. Openings may be provided in the C-shaped support members to permit the tines of a fork lift truck to be inserted between the layers of corrugated paperboard. Strips integral with the C-shaped members may project inwardly adjacent the openings and further provide additional protection for the polymeric blocks. Hence, the strips will minimize damage and tend to prevent the tines of a fork lift truck from destroying substantial portions of the blocks should the tines be improperly inserted into the openings in the C-shaped support members.

The C-shaped support members may be stapled or bonded to the layers of corrugated paperboard. In order to provide additional protection, the C-shaped support members may be glued or bonded to the exposed edges of the polymeric blocks to provide additional support thus obviating crushing of the pallet.

In another embodiment, the bottom layer of corrugated paperboard is eliminated. The top layer of paperboard is provided with appropriate score lines and envelops at least some of the blocks of polymeric material. When the blocks are utilized to support the center portion of the top layer, an intermediate strip of cardboard may be utilized to provide a base for such blocks. C-shaped support members may be utilized with this embodiment to further increase the strength and durability of the pallet.

For the purpose of illustrating the invention, there is shown in the drawings forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIG. 1 is a top plan view of one embodiment of the pallet of the present invention;

FIG. 2 is a side elevation view taken along line 2-2 of FIG. 1;

FIG. 3 is a perspective view of one of the blocks of rigid foam polymeric material;

FIG. 4 is a top plan view of an alternate construction of the embodiment of FIG. 1 of the pallet of the present invention;

FIG. 5 is a side elevation view of the pallet of FIG. 4;

FIG. 6 is a partial section view taken along line 6-6 of FIG. 5;

FIG. 7 is a top plan view of another embodiment of the pallet of the present invention;

FIG. 8 is a bottom plan view of the pallet of FIG. 7; and

FIG. 9 is a section view taken along line 9-9 of FIG. 7.

Referring now to the drawings in detail, wherein like numerals indicate like elements throughout the several views, there is shown in FIG. 1 a pallet designated generally as 10. The pallet 10 may be of any desired size. The pallet 10 includes a top layer of corrugated paperboard 12 and a bottom layer of corrugated paperboard 14.

The layers of paperboard 12 and 14 are superimposed over one another and are bonded to opposite faces of a plurality of longitudinally and laterally spaced blocks of rigid foam polymeric material 16, 18, 20, 22, 24, 26, 28, 30 and 32. The blocks of polymeric material are preferably made from foam polystyrene. The blocks 16, 18, 20 and 22 are disposed at the corners of the pallet. Blocks 16, 30 and 18 form a row along one side of the pallet. Blocks 20, 32 and 22 form a row along the opposite side of the pallet. A central row of blocks is formed by blocks 24, 26 and 28.

Channels 34, 36, 38 and 40 are provided so that the prongs or tines of a fork lift truck may be inserted thereinto to facilitate lifting and transferring a loaded pallet. The opposite faces of the blocks of foam polymeric material are adhesively bonded to the inner surfaces of the corrugated paperboard layers 12 and 14 by any suitable adhesive such as a commercially available rubber-base adhesive. It will be noted that the top and bottom faces of the blocks have surface area which is substantially larger tan the surface area of any of the sides or end faces of the blocks. In this manner, maximum support for layers 12 and 14 of corrugated paperboard is provided.

Each of the blocks has a plurality of holes extending therethrough. Referring to FIG. 3, block 20 is provided with six holes extending therethrough from the top face 44 to the bottom face thereof. Blocks 16, 30, 18, 22 and 32 are identical with block 20. Blocks 24, 26 and 28 are identical with block 20, except that they are larger and have a larger number of holes extending therethrough. For example, as shown in FIG. 1, the blocks 24, 26 and 28 will have nine holes extending therethrough.

The holes 42 in block 20, for example, enable the block 20 to be more consistently molded due to the holes providing for uniform heat distribution. As a result thereof, the blocks may be molded at a faster cycle rate than if the blocks were solid. It is desirable to mold the blocks since molding will produce a smooth surface finish. If the blocks are cut to size, a rough surface is presented requiring about 50 percent more glue than bonding the blocks to layers 12 and 14 of corrugated paperboard. Furthermore, since the blocks are sandwiched between layers of corrugated paperboard, air is trapped in the holes. As a result thereof, the blocks offer more resistance to crushing forces since the air will tend to be compressed as the crushing forces increase. The compressed air in the holes will resist deformation of the blocks.

The pallet 10 is provided with C-shaped support members 46 and 48 which are connected to the side edges thereof. The C-shaped support members 46 and 48 are substantially identical and hence only member 46 will be discussed in detail. The support members 46 comprises legs 50 and 52 which extend outwardly from an interconnecting web 51. The leg 50 is adapted to overlie layer 12 and leg 52 is adapted to overlie the layer 14. The legs 50 and 52 may be secured to the layers 12 and 14, respectively, by stapling, bonding or any other desired manner.

Preferably, the members 46 and 48 are also made of paperboard and may be made of corrugated paperboard. The exterior surface of each of the members may be wax coated to render the members water repellent The corrugated layers 12 and 14 may also be provided with wax-coated exterior surfaces to repel water. However, the flutes of the corrugated paperboard are exposed along the edges of the board and are subject to attack by water.

In the embodiment of FIG. 1, the C-shaped support members are attached to the sides of the pallet 10. Accordingly, the members 46 and 48 prevent water from contacting the flutes of the corrugated layers 12 and 14 from the sides thereof. It is to be noted that the blocks do not transmit water, and accordingly, the only way in which the top layer of corrugated paperboard could be destroyed by water is if the pallet were placed in several inches of water. However, even when this occurs, the preferred adhesive between the paperboard and the blocks will be water resistant and hence the pallet will still function in the desired manner.

Member 46 may be adhesively secured to the side edges of the blocks 20, 32 and 22 by a layer of adhesive 54. By adhesively securing a portion of the interior face of the web 51 to the blocks, the member 46 will cooperate with the blocks to resist deformation of the pallet 10. In the embodiment of FIG. 1, the members 46 and 48 do not have any openings therein and the tines of a fork lift truck must engage the pallet in the openings 34, 36, 38 or 40 on the opposite ends of the pallet 10.

The legs 50 and 52 extend inwardly a substantial distance on the pallet 10 in order to increase the sturdiness and durability of the pallet. The ends of the legs 50 and 52 may lie in substantially the same vertical plane which encompasses the innermost edges of the blocks 20, 32 and 22.

An alternate construction of the embodiment of FIG. 1 is illustrated in FIGS. 4--6. The pallet of FIG. 4 is generally designated as 10'. The pallet 10' is identical with pallet 10, except as will be made clear hereinafter. Hence, corresponding primed numerals are provided. C-shaped support members 56 and 58 are provided for the ends of the pallet 10'. The C-shaped support members 46', 48', 56 and 58 are provided with mitered edges so that a mitered joint is provided at each of the corners of the pallet. Since the members 46' and 48' are identical, only 46' will be discussed in detail.

Support member 46' has openings 60 and 62 therein. The openings 60 and 62 are identical and hence opening 60 will be discussed in detail. The C-shaped member 46' is die-cut along lines 64 and 66. The C-shaped member 46' is scored along lines 68 and 70. The score lines 68 and 70 permit the die-cut material to be bent thereat. Intermediate the score lines 68 and 70, a die cut is provided so that the material between the score lines 68 and 70 and the die-cut lines 64 and 66 form individual strips 72 and 74. The strips 72 and 74 are bent inwardly as shown in Figure 4. The strips 72 and 74 are adjacent one edge of the blocks 20' and 32', respectively, and provide protection for the blocks. Hence, if one of the tines of a fork lift truck is improperly inserted into the opening 60, strips 72 and 74 will be contacted prior to contact with the blocks and will provide protection for the blocks.

Inwardly projecting strips 76 and 78 are provided adjacent the opening 62. The member 48' is also provided with openings similar to 60 and 62 and with inwardly projecting strips as is shown in FIG. 4. Alternatively, the openings may be die-cut into the support members and all inwardly projecting strips eliminated.

The support members 56 and 58 are substantially identical. The members 56 and 58 are similar to the members 46 and 48 which were described in detail with reference to FIGS. 1 and 2. The members 56 and 58 may also each be provided with openings similar to openings 60 and 62 in the support member 46'.

The inwardly projecting legs of the support members 46', 48', 56 and 58 extend inwardly a substantial distance on the pallet 10' in order to provide support for the pallet. The ends of the legs of the support member 56 lie in substantially the vertical plane which is defined by the innermost vertical edge of the block 24. The legs of the support members 46' and 48' will preferably extend inwardly the same distance as the legs of the support members 56 and 58 as shown in FIG. 4.

The members 46', 48', 56 and 58 cooperate to prevent water from contacting the flutes of the corrugated layers 12 and 14 by covering the exposed edges of the layers. The durability and useful life of the pallet 10' is substantially increased by preventing water from attacking the corrugated layers 12 and 14.

Each of the support members 46', 48', 56 and 58 may have adhesive on the interior web thereof so that the support members may be secured to the edges of the rigid foam blocks. In this manner, the support members will cooperate with the blocks to resist deformation of the pallet 10'. A layer of adhesive 79 is shown connected to the interior surface of the web 51' of the support member 46' in FIG. 6. A similar layer of adhesive is shown secured to the interior surface of the web of the support member 58 and the other exposed surface of the block 20'.

Another embodiment of the present invention is illustrated in FIGS. 7--9. The pallet of FIG. 7 is generally designated as 100. The pallet 100 includes a top layer of corrugated paperboard 102.

The top layer of corrugated paperboard 102 has bonded to one face thereof a plurality of spaced blocks of rigid foam polymeric 104, 106, 108, 110, 112 and 114. The blocks are substantially identical in size to blocks 24, 26 and 28 of pallet 10. While six blocks are shown, it is readily apparent that a greater or lesser number of blocks may be utilized. The top layer of corrugated paperboard 102 has score lines therein to permit the ends thereof to envelop at least some of the blocks of the pallet. The left and right ends of the top layer of corrugated paperboard 102 as seen in FIG. 9 are substantially identical. Hence, only the left end will be described in detail.

The left end of the top layer of corrugated paperboard 102 has score lines 116, 118, 120, 122 and 124 therein. The paperboard is adapted to be folded along each of the score lines. When so folded, it is readily apparent that the board provides a sleeve 126 which envelops blocks 104 and 114 of the pallet 100. Similarly, a sleeve 128 is provided on the opposite end of the pallet 100 for enveloping the blocks 108 and 110. The sidewalls 125 and 127 of the sleeves 126 and 128, respectively, provide additional support for the pallet 100. Sidewall 125 may be secured to the blocks 104 and 114 and sidewall 127 may be secured to the blocks 108 and 110 by adhesive, staples or the like. In this manner, additional resistance is provided to deformation of the pallet 100.

By providing the sleeves 126 and 128, the pallet 100 is rendered substantially waterproof. The score lines tend to crush the flutes of the paperboard and hence substantially prevent the transmission of water throughout the layer 102. The layer 102 is preferably wax coated to render it waterproof. A sharp bend is provided at the score line 124 to minimize capillary action with regard to any water which may contact the end 130 of the top layer 102.

A flap 132 is bent back on a flap 134 and both of the flaps secured to the top layer 102. The flaps 132 and 134 may be stapled, glued or otherwise secured to the layer 102. When glue is utilized, the flap 132 will be first glued to the flap 134 thereafter the flap 134 may be glued to the layer 102.

A strip of corrugated paperboard 136 may be secured to the bottom faces of the polymeric blocks 106 and 112. The strip 136 may be glued or otherwise secured to blocks 106 and 112. It will be noted that there is no paperboard between the sets of blocks 104 and 114; 106 and 112; and 108 and 110 on the bottom of the pallet 100. Hence, hand lifting devices which are generally of the hydraulic type may be rolled along the floor inserted between the sets of blocks and utilized to move the pallet 100. The lifting device may be inserted in channels 140, 142, 144 or 146.

It is deemed readily apparent that when six blocks are utilized, such as in the embodiment of FIG. 7, the strip 136 may be eliminated and the score lines provided on the sides of the layer 102 rather than at the ends thereof. When the score lines are provided along the sides of the layer 102, one sleeve will envelop blocks 104, 106 and 108 and the other sleeve will envelop blocks 110, 112 and 114. When polymeric blocks are centrally located under the layer 102, it will be necessary to use at least one strip similar to strip 136.

C-shaped support members with openings therein similar to members 46' and 48' may be utilized to further increase the strength and durability of the pallet 100. However, the sleeves 126 and 128 which are integral with the layer 102 provide substantial support for the pallet and the pallet 100 may be reused many times without substantial deterioration of the pallet.

A pallet constructed in accordance with the present invention will weigh approximately three pounds as compared with a conventional pallet made from wood which may weigh approximately 15 pounds or more. It will be obvious to those skilled in the art that the weight of the pallet may vary with the size of the pallet. These figures are based on a pallet 60 inches long and 40 inches wide.

It should be noted with respect to the embodiment of FIGS. 1--6, that even if the bottom layer of corrugated paperboard were to become wet, the blocks of polymeric material would not transmit moisture by osmosis to the top layer 14. If a nail or other sharp surface is sticking up from the floor, the pallet 10, 10' or 100 may be positioned over the same without any substantial damage to it. That is, a sharp object such as a nail could pierce the layer 14 and enter one of the blocks without doing any substantial damage to the pallet. The pallet of the present invention can be tailored to fit many different situations and conditions. The size of the pallet and the number of blocks utilized may be varied as desired.

I have found that suitable dimensions for block 20 and those identical thereto are 2.times.6.times.10 inches, with holes 42 being 1.times.2 inches. Thus, the area of surface 44 is 48 square inches. I have found that suitable dimensions for block 24 and those identical thereto are 2.times.10.times.10 inches with holes therein being 2.times.2 inches. Thus, the area of the top surface of block 24 is 64 square inches. If maximum compressive strength is desired, some of the holes in blocks 24--28 may be filled by small blocks of wood. Other dimensions may be used for the polymeric blocks as long as the major area is on a face joined to a layer of corrugated paperboard. As illustrated, blocks 24, 26, 28, 104, 106, 108, 110, 112 and 114 distribute the load over a larger surface for more even distribution.

While a wide variety of polystyrene molding material is commercially available, I prefer to use DYLITE (Reg. T.M.) which has the following properties:

Thermal conductivity - 0.242 at 75.degree. F. mean temperature

Density - 2 lbs. per cu. ft.

Shock resistance - theoretical energy absorption of 60--70 1bs./sq. inch

compressive strength - 30 p.s.i.

Tensile strength - 50 p.s.i.

Water absorption - less than 0.9 percent during 48 hours

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification.

Claims

I claim:

1. A pallet comprising a plurality of spaced molded blocks of rigid foam polymeric material having smooth opposed major surfaces, a layer of corrugated paperboard fixedly secured to the top surfaces of said blocks, said layer of corrugated paperboard including sleeves at opposite ends thereof for encircling at least some of said foam polymeric blocks, said sleeve being integral with said layer, said sleeve including sidewalls adjacent the sides of said some of said foam polymeric blocks, said sleeves further including bottom walls for contacting the bottom faces of said some of said foam polymeric blocks, a further strip of corrugated paperboard fixedly secured only to the bottom faces of other of said foam polymeric blocks, said further strip having substantially the same width and length as the bottom wall of said sleeve, and said sidewalls of said sleeve cooperating with said foam polymeric blocks to resist deformation of said pallet.

2. A pallet as set forth in claim 1 wherein said layer of corrugated paperboard has score lines therein to facilitate forming of said sleeves, said layer of corrugated paperboard being wax coated to render said pallet substantially waterproof, said sleeve including additional sidewalls for contacting other side of some of said foam polymeric blocks, said other sidewalls having flaps connected thereto, and means securing said flaps to the under side of said layer of corrugated paperboard.

3. A pallet as set forth in claim 1 wherein the bottom of said pallet is open to permit the tines of a lifting vehicle to travel on the ground and be positioned under said pallet, said pallet being open between said sleeves and said further strip of corrugated paperboard, said pallet between said sleeves and said further strip of corrugated paperboard being substantially composed of a single thickness of corrugated paperboard.